As TiKV is a distributed transactional key-value database, transaction is a core feature of TiKV. In this chapter we will talk about general implementations of distributed transaction and some implementation details in TiKV.

Transactions provide an “all-or-nothing” proposition: each work-unit performed in a database must either complete in its entirety or have no effect whatsoever. Furthermore, the system must isolate each transaction from other transactions, results must conform to existing constraints in the database, and transactions that complete successfully must get written to durable storage.

A common algorithm for ensuring correct completion of a distributed transaction is the two-phase commit (2PC).